Assessment of sorghum anthracnose <i>(Colletotrichum sublineolum</i> P. Henn.) intensity and its association with biophysical factors in Western and Southwestern regions of Ethiopia

Abstract

Abstract Ethiopia is Africa's second‐largest sorghum producer [ Sorghum bicolor (L.) moench]. Despite these potentials, the production and productivity of sorghum yield remained low due to many agricultural factors. Among the factors, sorghum anthracnose caused by Colletotrichum sublineolum is one of the main fungal diseases substantially reducing sorghum grain yield. Hence, this study was undertaken to assess the intensity of anthracnose on sorghum fields, and its association with biophysical factors. Sorghum is the fifth most important cereal crop globally and a crucial food source for millions in sub‐Saharan Africa. In total, 350 sorghum fields (187 in 2020 and 163 in 2021) were surveyed during the main cropping seasons from October to November at the early to hard dough stages across the three regional states. Infected sorghum leaves were sampled and associated factors were identified. The results of this study revealed that the overall prevalence of sorghum anthracnose in sorghum fields across Western and Southwestern Ethiopia was 100%. Sorghum fields were shown varied levels of sorghum anthracnose incidences that ranged from 46.15% to 100% in Assosa, 55.5% to 100% in Jimma, 75% to 84.62% in Illubabor, 78.5% to 100% in East Wollega, and 85.7% to 100% in Gambella with the mean incidence of 83.78%, 85.81%, 78.10%, 78.57%, and 91.79.70%. Besides, the severity of anthracnose was high in Jimma, Assosa, Agnuwak, Illubabor, and East Wollega with mean field severity of 35.25%, 34.5%, 28.97%, 28.32%, and 27.60%, respectively. The study found that biophysical factors, such as proper weed management, crop rotation, recommended fertilizer application, sowing date, use of disease‐free seeds, and weather conditions were directly associated with sorghum anthracnose development.